In data communication networks, devices such as routers and switches are typically used to transfer data from a source to a destination. Existing switching systems often employ a switch fabric for switching data from source ports (also referred to as input ports) to destination ports (also referred to as output ports).
Fabric access devices are commonly used to manage data between the switch fabric and the rest of the system. A fabric access device may perform functions such as data buffering, data prioritization, redundancy management, etc. A typical fabric access device includes a single system interface configured to receive data from and send data to an external system or port. The configuration of such devices tends to have limited flexibility. For example, if redundancy is required, the fabric access device is typically connected to the switch fabric via two fabric interfaces. During normal operation, one of the fabric interfaces is active, and the other fabric interface is standing by. If the active fabric interface fails, the standby fabric interface takes over and continues to transfer data between the fabric access node and the switch fabric. Since twice the bandwidth on the fabric interface is required to service the bandwidth available on the system interface, such a configuration is said to provide full 2:1 redundancy. This approach is useful for providing a high level of redundancy since in the event that all of the active fabric interface links are lost, as long as the standby links can take over in time, no data will be lost. However, the highly redundant configuration also means that half of the available bandwidth on the fabric access interface remain idle in standby mode much of the time, resulting in inefficient utilization of bandwidth. In systems with less stringent redundancy requirements, it would be desirable if the fabric access device could allow more flexible configurations. For example, it may be useful to have fewer than half of the available interface links for redundancy purposes so that the available bandwidth is more efficiently utilized.